Positive active materials do not, in general, conduct electrons and it is necessary to add an electron conductor to them to provide the positive electrode with sufficient electron conductivity to convey the required currents, while avoiding presenting an initial voltage which is so high as to be incompatible with the utilization.
French published patent specification No. 2 316 756 describes various compositions of positive active masses intended to solve this problem. In particular, reducing agents which participate in the electrochemical reaction are added to the positive active masses, in proportions in the range of 10% to 20% by weight. However, in some special applications it is necessary to immediately obtain as low an impedance level as possible, or an impedance level which is close to the average discharge level, and the previously described means as inadequate for such applications since the initial impedance of the cells made in that way is high.
The present invention proposes to remedy this drawback and to supply an electrochemical cell having low initial impedance and whose initial voltage is practically the same as its operating voltage.